Several catalysts have been tried for hydrogenation reactions. These catalysts are usually based on metals such as palladium, platinum and nickel supported on different oxides like silica, different carbon supports like carbon nanotubes, and charcoal as well as several polymers. Out of all these catalysts, palladium on charcoal is the most frequently used catalyst in industries and academia.
Though Pd/C is frequently used by the industry, it has some drawbacks such as pyrophoric nature when in contact with dry methanol. Normally hydrogenation reactions are carried out at melting temperature and high hydrogen pressure. Conventionally triglycerides and unsaturated fatty acids are hydrogenated using noble metal based catalysts or copper chromite or copper cadmium catalysts at melting temperature in the range of 150 to 250° C. and high hydrogen pressure. Specifically oils like castor oils are hydrogenated using nickel based catalysts at melting temperature (150-250° C.) and high pressure (up to 20 bar). Under these severe conditions, highly dispersed palladium or platinum particles sinter leading to loss of catalytic activity. Many times the noble metal loading in industrial catalyst varies from 1% to 10% of the support and higher loading leads to increase in the catalyst cost.
To overcome the severe reaction conditions and to evolve a cheaper catalyst for hydrogenation reactions is the need of the time.